1. Field of the Invention:
This invention relates generally to a refrigeration apparatus and more particularly, it relates to a desuperheater control system for use in a refrigeration apparatus which regulates the superheat condition at all times to obtain partial heat recovery.
2. Description of the Prior Art:
In U.S. Pat. No. 3,301,002 issued to W. L. McGrath on Jan. 31, 1967, there is described an apparatus for heating water which includes a second compressor and condenser incorporated into a primary refrigeration system utilizing one of the heat exchange coils thereof as an evaporator.
In U.S. Pat. No. 3,188,829 issued to H. G. Siewert et al. on June 15, 1965, there is described a refrigeration system adapted for heating water which includes a heat exchanger disposed between the compressor and the condenser for bringing secondary medium to be conditioned into heat exchange relationship with the refrigerant and a pressure responsive valve operable to maintain a predetermined minimum refrigerant condensing pressure entering the evaporator.
In U.S. Pat. No. 4,123,914 issued to A. Perez et al. on Nov. 7, 1978, there is described a refrigeration system having a heat recovery section and a two-positioned valve responsive to external conditions to direct the flow of compressor discharge gases to the condenser or to the heat recovery section.
In U.S. Pat. No. 4,142,379 issued to H. W. Kuklinski on Mar. 6, 1979, there is shown an energy conservation device disposed between the compressor of an air conditioning unit and a conventional hot water heater for controlled water heating with rejected compressor heat.
In U.S. Pat. No. 4,146,089 issued to Mueller et al. on Mar. 27, 1979, there is shown a hot water system having a specially designed condenser from which large quantities of hot water is produced.
In U.S. Pat. No. 4,089,667 issued to K. A. Jonsson on May 16, 1978, there is disclosed a heat extraction system for air conditioning and refrigeration systems which includes a modified coaxial, counter-flow supplemental heat exchanger for heating water, the heat exchanger being disposed between a conventional compressor and condenser.
It is generally known that in air conditioning and refrigeration systems very large amounts of heat energy is normally dissipated into the surrounding air at the location of the condenser. In this age of energy conservation, it has become necessary to utilize the rejected heat from the air conditioning and refrigeration systems for some useful heating purpose, i.e., to heat water in a storage tank, and in the process, eliminate or reduce the consumption of other expensive fuel sources such as gas, electricity or oil. There are many prior art systems which act to conserve energy by absorbing the exhaust heat energy from the refrigerant for hot water heating using a supplemental heat exchanger at a location upstream of the conventional condenser. However, no provision has been made heretofore to control desuperheating selectively at all times to obtain partial heat recovery through a water regulating valve so as to insure maximum efficiency of the system.
The instant invention overcomes deficiencies in the prior art by providing a desuperheater control system which desuperheats the hot refrigerant gas from the compressor at all load conditions to within approximately 10.degree. F. of the saturated discharge pressure so as to avoid condensation. The employment of the present invention improves the coefficient of efficiency of the refrigeration apparatus by removing optimally the amount of superheat from the compressor gases and results in energy cost-savings due to the heating of water with rejected refrigeration heat at a minimal investment.